By The multiple Earths at DC had a nice purpose: when the heroes of the previous generation became too old for most readers to connect with, they were given their own space. In this case, a separate Earth, where they could grow and change in ways that were quite extraordinary at the time. Batman of Earth-2 was a prime example.
An excellent writer named Alan Brennert (who didn't work nearly enough in comics) produced a chapter of "The Autobiography of Bruce Wayne" in Brave and Bold 197. This told the story of how the Earth-2 Batman finally fell in love with Selina Kyle (Catwoman). One of the few Batman stories at that time told in first person, we see Bruce Wayne realizing that he's aging. With few friends to stand beside him, he wonders if he will wind up all alone. The damage his playboy persona had done troubles him: "…along the way, Bruce Wayne became frozen into someone I'd never intended him to be!"
The story features the Scarecrow as the villain, which plays into the emotional heart of the story. Scarecrow knows that Batman is afraid of losing everyone and concocts various drugs to make his friends disappear before him. Batman has no choice but to ask Selina Kyle (now reformed) for assistance. In the climax of the tale, even Selina begins to disappear in Batman's vision. She unmasks herself and asks him to do the same. When Batman does, they kiss, and it's at that moment that Batman retires and Bruce Wayne begins to live again. He's finally overcome the emotional demons that have dogged him since his parents were killed.
Paul Levitz (now the publisher of DC Comics) wrote the rest of Bruce Wayne's final years across a number of series. In DC Super-Stars #17, featuring the origin of the Huntress, we see Batman's wedding to Selina on the first page. Wayne becomes Police Commissioner while Robin becomes an adult, adopts a more mature costume, and takes care of Gotham City. Meanwhile, Selina gives birth to their daughter Helena Wayne. They all presumably have happy lives until Selina becomes a young woman.
Of course, happiness can't last forever. A criminal blackmails Selina into pulling one last job, because she killed a man many years earlier, and never told Wayne the full truth. During a museum robbery, things go haywire when Wayne becomes Batman temporarily to stop it (Robin is out of town) and accidentally causes a stray bullet to hit Selina. She falls to her death and dies in Wayne's arms. It's this event that propels Helena to become the Huntress-her first mission avenges her mother's death.
Bruce Wayne becomes a supporting player in the JSA's series in All-Star Comics that ran during the 70s. When that series was cancelled, the team appeared in Adventure Comics for a few issues. The story that took place in Adventure 461-462 was the final story of Bruce Wayne. The JSA is attacked by Bill Jensen, an ordinary criminal suddenly gifted with magical powers. Jensen demands to see Bruce Wayne-he thinks Wayne framed him years ago. Wayne becomes the Batman one last time, and faces down Jensen. His homicidal rage consumes both of their lives.
Wayne's funeral is attended by the heroes of Earth-2 and Earth-1. At first Robin wants to become the Batman, but Helena tells him: "There was only one man who could be the Batman, Dick, and my father is dead. We can carry on his work-you as Robin, me as the Huntress…but the Batman is dead. Only legends live forever…not the men who make them." Nuff said.
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